Add initial news reader example (#4348)

doc/source/index.rst

@@ -115,6 +115,7 @@ Ray comes with libraries that accelerate deep learning and reinforcement learnin
    example-rl-pong.rst
    example-policy-gradient.rst
    example-parameter-server.rst
+   example-newsreader.rst
    example-resnet.rst
    example-a3c.rst
    example-lbfgs.rst